Error installing symbolic toolbox

We are facing error installing symbolic toolbox for Scilab. We are following the instructions given onhttps://scilab.in/scilab-symbolic-toolboxbut we are facing error at the 11th line (Type exec loader.sce in Scilab console).The screenshot of the error is attached here (https://ibb.co/ccKK9HH).Kindly assist us in resolving the issue.

Scilab Not Spam 25-04-18, 7:22 p.m. dhruvpalrecha